Octothorpe means: The hash or square symbol #, used mainly in telephony and computing.. There is no real cause for parental concern; it is descriptive vocabulary rather than risky behaviour. If your teen uses it, context will usually make the intent clear. A short, curious question about where they heard it is usually all that is needed to know whether to follow up.
octothorpe
(chiefly, US, typography) The hash or square symbol #, used mainly in telephony and computing.
ˈɒktəʊθɔːpDocumented since 1960s1960sBoomerhistoricalCurrent181 viewsLast reviewed Jun 29, 2026＋ Add a definition
Etymology timeline
Born ~1960 · 1 year of recorded useBoomer / counterculture eraSee decade cohort →
Definitions
US
#1·Apr 27, 2026US
(chiefly, US, typography) The hash or square symbol #, used mainly in telephony and computing.
Origin: Origin . There is no known usage before it was adopted by Bell Labs in the late 1960s or early 1970s, so most sources agree it was coined by someone at Bell Labs, but accounts from Bell Labs personnel conflict on the details. The derivation as a traditional term from lacks any evidence, but there is near universal agreement that the first element refers to the number eight. Eight is derived from the number of ends of the lines. Thorpe could be a reference to Jim Thorpe, as one proponent was a fan of the athlete. However, it probably is just an arbitrarily-picked syllable with no particular. Origin information sourced from Wiktionary contributors (CC BY-SA 4.0).
For parents
Octothorpe means: The hash or square symbol #, used mainly in telephony and computing.. There is no real cause for parental concern; it is descriptive vocabulary rather than risky behaviour. If your teen uses it, context will usually make the intent clear. A short, curious question about where they heard it is usually all that is needed to know whether to follow up.
For ESL learners
octothorpe means: The hash or square symbol #, used mainly in telephony and computing.. Register: neutral, standard English. A common learner mistake is using the word in a register it does not fit, or assuming a single global meaning; native speakers immediately notice when slang appears in formal contexts, so always check the surrounding register before producing it yourself. A formal-English equivalent (a synonym or descriptive phrase) is usually safer in writing. When in doubt, paraphrase rather than reuse the slang form.
Cluster: square_person
Heard in the wild
“@octothorpe we have a couple of engineers who have absolutely no clue and totally barge in on people deeply concentrating without remorse. It’s super awkward.”
— Bluesky· May 2026
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For specific readers
Why is this section here?
Slang is read by different audiences for very different reasons. The For parents view re-explains the term in plain, non-judgemental language so a caregiver can understand what their child means without needing the surrounding subculture. The For English learners view focuses on register (when it's safe to use), formal alternatives, and common mistakes — what a textbook won't teach you.
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Other words near "octothorpe" (O)
octavofinaloctillionoctochampoctodecillionoctogintillionoctopushoctovigintillionocupadoODODCodd and curiousodd bod
Browse all slang words starting with O.
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